Finland, a country stretching into the Arctic Circle, experiences extraordinary light conditions. While the sun does indeed set, its behavior varies dramatically with the seasons, leading to periods of continuous daylight and extended twilight. This unique geographical position results in a dynamic interplay of light and darkness throughout the year.
The Midnight Sun in Finland
During the summer months, regions of Finland north of the Arctic Circle experience the phenomenon known as the Midnight Sun, or “yötön yö” (nightless night). This occurs when the sun remains visible for 24 hours a day, never dipping below the horizon. In Utsjoki, Finland’s northernmost municipality, the sun stays above the horizon for approximately 70 days, typically from late May to early August. Further south, in Rovaniemi, located directly on the Arctic Circle, the Midnight Sun is observed from early June to early July, lasting about a month.
Continuous daylight bathes the landscape in a warm, often reddish-yellow light, similar to prolonged sunrise or sunset. The sun travels in a low arc across the sky. Even in southern areas like Helsinki, while the sun briefly sets, the nights remain remarkably bright with extended twilight periods, creating what locals call “white nights.” This allows for outdoor activities to continue around the clock.
The Polar Night in Finland
Conversely, winter brings the Polar Night, known as “Kaamos” in Finnish, to the northernmost parts of the country. This phenomenon describes a period when the sun does not rise above the horizon for more than 24 hours. In Utsjoki, the Polar Night can last for nearly two months, from late November to mid-January. Even in Rovaniemi, the sun may only appear for a few hours around noon.
Despite the term “Polar Night,” it is not a period of complete darkness. The sky often transitions through prolonged twilight, creating a “blue moment” around midday. During this time, the sky can display soft hues of deep blues, purples, and pinks, especially when reflected by the snow-covered landscape. This light results from the sun’s rays hitting the upper atmosphere, producing a glow comparable to sunset.
Understanding the Earth’s Tilt
Both the Midnight Sun and Polar Night are direct consequences of Earth’s axial tilt. Our planet spins on an axis that is tilted approximately 23.5 degrees relative to its orbit around the sun. This tilt means that as Earth revolves around the sun, different parts of the planet receive varying amounts of direct sunlight throughout the year.
During the Northern Hemisphere’s summer, the Earth’s tilt causes Arctic regions to lean towards the sun. This keeps the sun continuously above the horizon for areas within and north of the Arctic Circle (approximately 66.5 degrees North latitude). Conversely, during winter, these regions tilt away from the sun, causing it to remain below the horizon for extended periods, leading to Polar Night. The Arctic Circle marks the southernmost latitude where, at least one day a year, the sun does not set or rise.
Life Under Extreme Light and Dark
Living with pronounced shifts in daylight cycles influences daily life and routines in Finland. During the summer’s continuous daylight, many Finns adjust their sleep patterns and social activities, embracing the extended hours for outdoor pursuits like hiking, fishing, and enjoying lakeside cottages. The “nightless night” facilitates a vibrant period of activity and celebration, including the traditional Midsummer festivities.
Conversely, the long periods of winter darkness require different adaptations. Reduced sunlight can affect mood and energy levels. Seasonal variation in mood and behavior is common among Finnish adults, with some experiencing symptoms resembling seasonal affective disorder (SAD). To manage the darker months, people may use bright light therapy or spend time outdoors during the brief twilight hours.